Composite tool

ABSTRACT

A composite working tool having a working surface and a desired direction of metal working and power transmitting movement comprising a composite composed of two bodies, each of a different metal; one of said metals being harder than the other and being the working surface. The two of said bodies are in direct contact with each other along a plane substantially perpendicular to said direction of movement whereby power is transmitted from one of said bodies to the other across said plane when said composite working tool is moved. One of said bodies has a narrowed portion and the other of said bodies has an opening defined therewithin to receive said narrowed portion. Each of said narrowed portion and said opening have defining walls in the desired direction of movement of the tool. The defined opening is larger in size than the narrowed portion to receive the same therein with clearance between said defining walls. Brazing filler metal is positioned in said clearance between said defining walls to bond the same together in the desired direction of movement of said tool. The working surface of said composite tool is preferably a hard metal carbide and the other metal of said tool is preferably a steel shank. The composite tool is preferably manufactured utilizing cooling of the steel shank when the hard solder is heated.

United States Patent is 3,677,060 Loqvist July 18, 1972 54] COMPOSITETOOL OTHER PUBLICATIONS 72 I t K is Fa ersta 8 ed Techniques ofPressworking Sheetmetal, Eary, D. F. and 1 8 w Reed, E. A., 1958, DieDesgin Techniques, p. 354, FIG. 263 [73] Assignee: Fagersta BruksAktiebolag, Fagersta,

Sweden Primary Examiner-Richard J. Herbst 22] Filed: June 24, 1970Attorney-Bauer and Goodman [2]] Appl. No.: 49,314 [57] ABSTRACT Acomposite working tool having a working surface and a [30] Foreign A liti priority m desired direction of metal working and power transmittingY movement comprising a composite composed of two bodies, June 27,Sweden each ofa difi'erent meta]; one of metals harder than the otherand being the working surface. The two of said [52] U.S. Cl. ..72/476,29/473. 1 76/107 A bodies are in direct contact with each other along aplane sub- [Sl] Int. I 321d 37/00 stantially perpendicular to saiddirection of movement [58] Field of Search ..72/476, 479, 480, 478, 273,whereby power is transmitted from one of said bodies to the 72/267, 283,209; 76/101 A, 101 R, 102 A; other across said plane when said compositeworking tool is 29/473.l, 474.4, 479, 489 moved. One of said bodies hasa narrowed portion and the other of said bodies has an opening definedtherewithin to 56 References Cit d receive said narrowed portion. Eachof said narrowed portion and said opening have defining walls in thedesired direction UNITED STATES PATENTS of movement of the tool. Thedefined opening is larger in size than the narrowed portion to receivethe same therein with g l z clearance between said defining walls.Brazing filler metal is l 935 Stung e g A positioned in said clearancebetween said defining walls to 2'019934 1 1/1 chroter at bond the sametogether in the desired direction of movement 2,124,438 Struk 6t 31........76/l0l A of said tool. working surface of i composite tool is2,418,338 4/1947 Dworkowsk i 101 A preferably a hard metal carbide andthe other metal of said 2,474,643 6/1949 \Yebb ....76/ 101 A tool ispreferably a steel Shank The composite l is 3,180,023 4/ 1965 Titus..29/473.l f bl f t d utilizing cooling f the steel Shank when the hardsolder is heated.

2 i e ns s 1 i F J I 25 f 1? 1 Z 1 i 5 4 I i U 2. 25 A y fr a 22 v I4 I223 ,8 M 1 l l i i I3 minimums I912 F/Gl INVENTOR. KAJ-RAGNAR ATTORNEYSCOMPOSITE TOOL BACKGROUND OF THE INVENTION Hardened steel tools such asplungers for deep drawing, punching, etc., which are faced with hardmetal carbides on the working surface are difficult to manufacture andwhen manufactured have limited durability. This is in part caused by thedifference in linear expansion of the steel tool body and that of thehard metal carbide working face which results in differentialcontracting during the manufacture of the tool and a consequentreduction in durability, especially resistance to fatigue, in andadjacent to the joint between the shank and the working face caused bystresses in said joint. The present invention provides improvedcomposite tools having a hard metal carbide working face.

SUMMARY OF THE INVENTION A composite working tool having a workingsurface and an axial direction of metal working movement and of powertransmission, said composite tool comprising a power transmitting bodyand a working body having said working surface, said working body beingcomposed of hard metal carbide and being harder than said powertransmitting body, said power transmitting body and said working bodybeing in direct contact with each other along a plane substantiallyperpendicular to said axial direction whereby power is transmitted fromone of said bodies to the other across said plane, one of said bodieshaving a narrowed portion and the other of said bodies having an openingdefined therewithin to receive said narrowed portion, each of saidnarrowed portion and said opening having defining walls in the saidaxial direction, said defined opening being larger in size than saidnarrowed portion to receive the same therein with clearance between saiddefining walls, and brazing filler metal in said clearance andpositioned between said defining walls to bond the same together in thesaid direction of power transmission of said tool. The composite toolhas a hard metal carbide working surface bonded to a steel shank. Thedefining wall of the opening in the steel shank forms a collar whichsurrounds the male portion of the hard metal carbide.

The invention also provides a method for producing the foregoingcomposite tool in which the shank is cooled while the brazing fillermetal is heated to form the bonded joint. When applied to the compositetool of FIG. 1, the process comprises applying brazing filler metal insaid clearance between the collar of the steel shank and said maleportion of the hard metal carbide, and heating said brazing filler metalto substantially its melting point while cooling said steel shank.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a partial sectionalelevation of one embodiment of the invention; and

FIG. 2 is an elevation of a second embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference is first made to FIG.1 depicting a cross-section of a composite tool of the present inventiontogether with apparatus utilized in manufacturing said composite tool10. The intended working direction of tool 10 is substantially axialalong axis 24. The composite tool 10 has a steel shank 11 with adownwardly extending rim or collar 16 positioned around neck 19 whichextends upwardly from the hard metal carbide facing 13. Neck 19 isjoined to collar 16 along longitudinal joint 14 by brazing filler metal.The brazing filler metal preferably also extends along the joint 18formed in the clearance between the farthest extending surface 20 ofcollar 16 and the shoulder 21 of the hard metal carbide facing 13.

The use of brazing filler metal for joining such metals as steel andhard metal carbides involves utilizing a metal which at room temperatureis harder than the widely used so-called tin solder and which has ahigher melting point than said tin solder. The brazing filler metals areillustrated by silver solder and copper solder. Brazing utilizingbrazing filler metal involves heating the steel and hard metal carbideto at least a temperature which is about the same as the melting pointof the brazing filler metal. A common brazing temperature for joiningsteel and hard metal carbide with a silver solder is about 800 C.

During production of the tool 10 in which the joints are heated and thebrazing filler metal applied in the clearance between collar 16 and neck19 to form joint 14, heating of the body of steel shank 11 is minimizedby the cooling shoe 12. This results in preventing or minimizingpossible softening of steel shank 11 as a consequence of the hightemperature joining operation. The cooling effect resultant from theapplication of cooling shoe 12 also serves to prevent brazing fillermetal from penetrating joint 17 between the lower face 22 of steel shank11 and the upper face 23 of the neck 19 of the hard metal carbide facing13. The cooling shoe 12 may be water cooled, e.g., by passage of waterthrough channel 25 illustrated in outline by dotted lines. The brazedjoint 14 is disposed as a ring between the neck 19 of the hard metalcarbide facing 13 and the collar 16 of the steel shank 11 and isgenerally parallel to the direction of the applied force during theoperation of the tool 10 resultant in only relatively slight fatiguepotentialities therein.

FIG. 2 illustrates an embodiment of the invention particularlyadvantageous for large composite punches. The large composite punch 30has a steel shank 31 and a hard metal carbide facing 32. The steel shank31 has a downwardly extending collar 33 with circumferentially spacedslots 35 therealong. The hard metal carbide facing 32 has an upwardlyextending neck 34 fitted into the collar 33.

The slots 35 function to reduce heat stress during cooling after thebrazing operation. This is particularly advantageous when manufacturinglarge composite tools. It is also preferable that sufficient brazingfiller metal be used during the brazing operation so that in addition tothe clearance between the inner cylindrical surface of the collar 33 andthe outer cylindrical surface of neck 34 being filled with brazingfiller metal, filler metal also fills the slots 35.

The composite tools of the present invention preferably have a toolsteel shank and a working surface of a sintered carbide such as tungstencarbide andlor titanium carbide and/or tantalum carbide.

As many embodiments of this invention may be made without departing fromthe spirit and scope thereof, it is to be understood that the inventionincludes all such modifications and variations as come within the scopeof the appended claims.

What is claimed is:

l. A composite working tool having a working surface and an axialdirection of metal working movement and of power transmission,

said composite tool comprising a power transmitting body and a workingbody having said working surface, said working body being composed ofhard metal carbide and being harder than said power transmitting body,

said power transmitting body and said working body being in directcontact with each other along a plane substantially perpendicular tosaid axial direction whereby power is transmitted from one of saidbodies to the other across said plane,

one of said bodies having a narrowed portion and the other of saidbodies having an opening defined therewithin to receive said narrowedportion,

each of said narrowed portion and said opening having defining walls inthe said axial direction,

said defined opening being larger in size than said narrowed portion toreceive the same therein with clearance between said defining walls, and

brazing filler metal in said clearance and positioned between saiddefining walls to bond the same together in the said direction of powertransmission of said tool.

2. The composite tool of claim 1 wherein said power transmitting body isa steel shank and wherein said body having said narrowed portion is maleshaped and said other body is female shaped.

3. The composite tool of claim 2 wherein said working body has saidnarrowed portion.

4. The composition tool of claim 3 wherein the defining wall of saidopening forms a collar which surrounds said male portion of said workingbody.

5. The composite tool of claim 4 wherein there is provided a secondclearance between said bodies in the direction substantially normal tothe direction of metal working movement and positioned at the end ofsaid collar, and wherein brazing filler metal is in said secondclearance.

6. The composite tool of claim 5 wherein said collar has a plurality ofslots circumferentially spaced along said collar.

7. The composite tool of claim 6 wherein brazing filler metal ispositioned in said slots.

8. A composite metal working tool having a desired direction of workingmovement and power transmission, said tool comprising a first body ofsteel, a second body of hard meta] carbide, said two bodies havingdissimilar heat expansion characteristics and hardness,

said first body of steel and said second body of hard metal carbidebeing in direct contact with each other along a plane substantiallyperpendicular to said direction of working movement and powertransmission, whereby power is transmitted from one of said bodies tothe other across said plane when said composite tool is moved in saiddirection,

one of said bodies having an elongated portion extending from the mainportion of said body in the direction of the working movement of thetool,

the other of said bodies having an elongated extension complementary tosaid first mentioned elongation and in the direction of working movementof said tool with a clearance defined between said complementaryelongations said first mentioned elongation having a plurality of slotscircumferentially spaced along the length of said elongation, and

brazing filler metal in said slots and in said clearance bonding saidcomplementary elongations together in the direction of movement of thetool.

9. The composite metal working tool of claim 8 wherein there is a secondclearance between the end of said first mentioned elongation and saidother body and wherein hard solder is positioned in said secondclearance.

10. The composite metal working tool of claim .9 wherein said firstmentioned elongation is a steel body shank, wherein said secondmentioned elongation is a collar, and wherein said second body of hardmetal carbide is a tool working surface.

11. A process for producing a composite tool having a working surfaceand an axial direction of metal working movement and of powertransmission, said composite tool comprising a power transmitting bodyand a working body having said working surface, said working body beingcomposed of hard metal carbide and being harder than said powertransmitting body, said power transmitting body and said working bodybeing in direct contact with each other along a plane substantiallyperpendicular to said axial direction whereby power is transmitted fromone of said bodies to the other across said plane, one of said bodieshaving a narrowed portion and the other of said bodies having an openingdefined therewithin to receive said narrowed portion, each of saidnarrowed portion and said opening having defining walls in the saidaxial direction, said defined opening being larger in size than saidnarrowed portion to receive the same therein with clearance between saiddefining walls, and brazing filler metal in said clearance andpositioned between said defining walls to bond the same together in thesaid direction of power transmission of said tool comprisinfi applyingbrazing fi er metal in said clearance between the collar of the steelshank and said male portion of the hard metal carbide, and

heating said brazing filler metal to substantially its melting pointwhile cooling said steel shank.

12. The process of claim 11 wherein said steel shank is cooled byplacing a cooling shoe in peripheral contact therewith.

1. A composite working tool having a working surface and an axialdirection of metal working movement and of power transmission, saidcomposite tool comprising a power transmitting body and a working bodyhaving said working surface, said working body being composed of hardmetal carbide and being harder than said power transmitting body, saidpower transmitting body and said working body being in direct contactwith each other along a plane substantially perpendicular to said axialdirection whereby power is transmitted from one of said bodies to theother across said plane, one of said bodies having a narrowed portionand the other of said bodies having an opening defined therewithin toreceive said narrowed portion, each of said narrowed portion and saidopening having defining walls in the said axial direction, said definedopening being larger in size than said narrowed portion to receive thesame therein with clearance between said defining walls, and brazingfiller metal in said clearance and positioned between said definingwalls to bond the same together in the said direction of powertransmission of said tool.
 2. The composite tool of claim 1 wherein saidpower transmitting body is a steel shank and wherein said body havingsaid narrowed portion is male shaped and said other body is femaleshaped.
 3. The composite tool of claim 2 wherein said working body hassaid narrowed portion.
 4. The composition tool of claim 3 wherein thedefining wall of said opening forms a collar which surrounds said maleportion of said working body.
 5. The composite tool of claim 4 whereinthere is provided a second clearance between said bodies in thedirection substantially normal to the direction of metal workingmovement and positioned at the end of said collar, and wherein brazingfiller metal is in said second clearance.
 6. The composite tool of claim5 wherein said collar has a plurality of slots circumferentially spacedalong said collar.
 7. The composite tool of claim 6 wherein brazingfiller metal is positioned in said slots.
 8. A composite metal workingtool having a desired direction of working movement and powertransmission, said tool comprising a first body of steel, a second bodyof hard metal carbide, said two bodies having dissimilar heat expansioncharacteristics and hardness, said first body of steel and said secondbody of hard metal carbide being in direct contact with each other alonga plane substantially perpendicular to said direction of workingmovement and power transmission, whereby power is transmitted from oneof said bodies to the other across said plane when said composite toolis moved in said direction, one of said bodies having an elongatedportion extending from the main portion of said body in the direction ofthe working movement of the tool, the other of said bodies having anelongated extension complementary to said first mentioned elongation andin the direction of working movement of said tool with a clearancedefined between said complementary elongations said first mentionedelongation having a plurality of slots circumferentially spaced alongthe length of said eloNgation, and brazing filler metal in said slotsand in said clearance bonding said complementary elongations together inthe direction of movement of the tool.
 9. The composite metal workingtool of claim 8 wherein there is a second clearance between the end ofsaid first mentioned elongation and said other body and wherein hardsolder is positioned in said second clearance.
 10. The composite metalworking tool of claim 9 wherein said first mentioned elongation is asteel body shank, wherein said second mentioned elongation is a collar,and wherein said second body of hard metal carbide is a tool workingsurface.
 11. A process for producing a composite tool having a workingsurface and an axial direction of metal working movement and of powertransmission, said composite tool comprising a power transmitting bodyand a working body having said working surface, said working body beingcomposed of hard metal carbide and being harder than said powertransmitting body, said power transmitting body and said working bodybeing in direct contact with each other along a plane substantiallyperpendicular to said axial direction whereby power is transmitted fromone of said bodies to the other across said plane, one of said bodieshaving a narrowed portion and the other of said bodies having an openingdefined therewithin to receive said narrowed portion, each of saidnarrowed portion and said opening having defining walls in the saidaxial direction, said defined opening being larger in size than saidnarrowed portion to receive the same therein with clearance between saiddefining walls, and brazing filler metal in said clearance andpositioned between said defining walls to bond the same together in thesaid direction of power transmission of said tool comprising applyingbrazing filler metal in said clearance between the collar of the steelshank and said male portion of the hard metal carbide, and heating saidbrazing filler metal to substantially its melting point while coolingsaid steel shank.
 12. The process of claim 11 wherein said steel shankis cooled by placing a cooling shoe in peripheral contact therewith.